An upper tool holder for holding an upper tool is provided at a lower portion of an upper table of a press brake. The upper tool holder includes a holder main body attached to the lower portion of the upper table, and a clamp attached to the holder main body. The clamp is swingably attached to the holder main body. In addition, the holder main body also includes a fluid pressure cylinder that has a piston rod for pushing an upper portion of the clamp forward. The fluid pressure cylinder is able to stroke the piston rod backward and forward. Then, at a pushed position of the clamp by an end of the piston rod, a screw member as a pushed member is screwed movably backward and forward (e.g. Patent Document 1 listed below).
In the upper tool holder, a lower portion of the clamp is swung backward when the end of the piston rod of the fluid pressure cylinder pushes the screw member forward, and thereby the upper tool is held between the clamp and the holder main body. On the other hand, when working fluid pressure of the fluid pressure cylinder is reduced, the upper tool is unclamped. In an unclamped state of the upper tool, a wedge piece attached to the lower portion of the clamp engages with a drop prevention groove formed laterally on the upper tool, and thereby the upper tool is held laterally-slidably by the upper tool holder.
Therefore, when exchanging a laterally long upper tool by sliding it laterally, the upper tool can be prevented from dropping off and operations for exchanging the upper tool can be done safely.
In the above-explained upper tool holder, when exchanging a laterally long upper tool from beneath of the upper tool holder, the clamp is widely opened. In this case, since the clamp cannot be widely opened when the above-explained screw member and the end of the piston rod are contacted with each other, the screw member is retracted into the clamp by being turned. By avoiding contacts between the screw member and the end of the piston rod, the upper tool can be exchanged from beneath of the upper tool holder by opening the clamp widely to disengage the wedge piece from the drop prevention groove.